细菌群落通过增加丰度、多样性与构建协同共生模式适应干旱气候环境

Bacterial communities adapt to arid climatic environments by increasing abundance and diversity and constructing synergistic patterns

摘要:

目的 探讨细菌群落生物特征对长期气候变化的响应关系。方法 采用石峁(Y)、坡头(P)和任家坡(R)三地50万年以来的黄土(YL、PL和RL)-古土壤(YS、PS和RS)序列不同类型土壤，运用高通量测序技术及FAPROTAX细菌群落功能预测数据库等生物信息学方法分析土壤细菌群落结构与功能差异。结果 三地在黄土-古土壤交替下的理化因子特征与土壤发育过程中干冷、暖湿的气候变化存在一致性。同一时期，任家坡气候特征最为温暖湿润，受夏季风影响最大，坡头次之，石峁最为干冷。细菌群落丰度与多样性指数均表现为石峁大于坡头和任家坡。三地共有变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、酸杆菌门(Acidobacteria)等优势菌门，但丰度差异显著。石峁细菌群落在黄土和古土壤组成更为相似且通过协同作用构建网络结构。细菌群落在三地黄土-古土壤序列中表达的生态功能主要为碳、氮、硫元素循环，其中石峁的碳、氮循环表达较弱，坡头的氮循环较为突出，任家坡表现出较强的碳循环。结论 暖湿气候下的细菌群落具有更复杂的网络结构，表现出更丰富的功能多样性；干冷气候下的细菌群落组成更相似，并通过增加丰度与多样性来补偿低碳、氮循环带来的营养不足，维持协同共生模式以适应环境。

Abstract:

Objective To study the response relationship of the biological properties of bacterial communities to long-term climate change.Methods The loess (YL, PL, and RL) and paleosol (YS, PS, and RS) sequences, which have persisted for approximately 500 000 years at Shimao (Y), Potou (P), and Renjiapo (R), were sampled. The structures and functions of the soil bacterial communities were predicted by bioinformatics approaches, including high-throughput sequencing and FAPROTAX.Results The physical and chemical characteristics associated with the loess-paleosol alternation in the three regions reflected the shifts in climatic conditions, including dry, cold, warm, and wet phases during soil development. Over this period, the climate at Renjiapo was characterized by the highest temperatures and precipitation levels, with strong influences from summer winds. Shimao experienced the driest conditions and the lowest temperatures. Potou exhibited the intermediate climatic conditions between Renjiapo and Shimao. The abundance and diversity indices of the bacterial communities in Shimao were higher than those in Potou and Renjiapo. Across all the three regions, the dominant bacterial phyla were Proteobacteria, Actinobacteria, and Acidobacteria although their relative abundance varied significantly. The bacterial communities in the loess and paleosol layers of Shimao showed greater compositional similarity, forming a network structure driven by synergistic interactions. The ecological functions of the bacterial communities in the loess-paleosol sequences were primarily associated with carbon, nitrogen, and sulfur cycling. Carbon and nitrogen cycling was weakly expressed in Shimao, while nitrogen cycling was more prominent in Potou. Renjiapo exhibited the most pronounced carbon cycling.Conclusion Soil bacterial communities in warm and humid climates tend to exhibit more complex network structures and greater functional diversity. In contrast, bacterial communities in dry and cold climates are characterized by similar composition and synergistic patterns, which enable these communities to adapt to harsh conditions by increasing their abundance and diversity, compensating for nutrient limitations associated with reduced carbon and nitrogen cycling.